Performance of soft-decision linear receivers for spatial-multiplexing FBMC/OQAM

With the increasing demand for mobile data traffic, enhanced frequency localized transmissions are considered for the generation of wireless networks to come. Filter Bank Multi-Carrier modulation, with the use of Offset-QAM, proves to be an interesting candidate to satisfy those spectrum constraints. Contrary to CP-OFDM, FBMC does not use any CP. Its spectral efficiency is improved but it also weakens the transmissions over highly frequency selective channels. Complex detection stage based on precoding or multi-tap equalization is thus necessary to prevent orthogonality losses. Another solution can be the use of the Frequency-Spreading scheme which improves the frequency resolution. In this paper, we propose to extend probabilistic decoding to linear FBMC receivers. The performances of the two common FBMC receiver structures, PolyPhase Network and Frequency-Spreading, are assessed over frequency-selective LTE channel models. The analytical formulae of the likelihood metrics are also derived.